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The Ductile to Brittle Transition Behavior of the Modified 9cr-1Mo Steel and Its Laser Welds

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材料导报 2004年第8期18卷 121-123页

作者： h.c.wu R.K.Shiue c.chen DepartmentofMaterialsScienceandEngineering TaiwanUniversityTaipei106ChinaTaiwan DepartmentofMaterialsScienceandEngineering DongHwaUniversityHualien974ChinaTaiwan

The ductile to brittle transition temperature (DBTT) of the modified 9cr-1Mo steel and its laser welds was studied. The increase in grain size of the weld structure ascended the DBTT of the steel significantly. The transformation of retained austenite at martensite interlath boundaries into untempered and/or twinned martensite could also contribute to increased DBTTs of the steel and its welds tempered at 540℃.

关键词： 9cr-1Mo钢激光焊接 DBTT 冲击韧性

The Ductile to Brittle Transition Behavior of the Modified 9cr-1Mo Steel and Its Laser Welds

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The Ductile to Brittle Transition Behavior of the Modified 9...

The Lobster Eye Imager for Astronomy Onboard the SATech-01 Satellite

海峡两岸第二届工程材料研讨会

作者： h.c.wu R.K.Shiue c.chen Department of Materials Science and Engineering Taiwan University Taipei 106 China Taiwan Department of Materials Science and Engineering Dong Hwa University Hualien 974 China Taiwan Department of Materials Science and Engineering Taiwan University Taipei 106 China Taiwan

关键词： modified 9cr-1Mo steel laser welding impact toughness ductile to brittle transition temperature

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天文和天体物理学研究:英文版 2023年第9期23卷 66-78页

作者： Z.X.Ling X.J.Sun c.Zhang S.L.Sun G.Jin S.N.Zhang X.F.Zhang J.B.chang F.S.chen Y.F.chen Z.W.cheng W.Fu Y.X.han h.Li J.F.Li Y.Li Z.D.Li P.R.Liu Y.h.Lv X.h.Ma Y.J.Tang c.B.Wang R.J.Xie Y.L.Xue A.L.Yan Q.Zhang c.Y.Bao h.B.cai h.Q.cheng c.Z.cui Y.F.Dai D.W.Fan h.B.hu J.W.hu M.h.huang Z.Q.Jia c.c.Jin D.Y.Li J.Q.Li h.Y.Liu M.J.Liu Y.Liu h.W.Pan Y.L.Qiu M.Sugizaki h.Sun W.X.Wang Y.L.Wang Q.Y.wu X.P.Xu Y.F.Xu h.N.Yang X.Yang B.Zhang M.Zhang W.D.Zhang Z.Zhang D.h.Zhao X.Q.cong B.W.Jiang L.h.Li X.B.Qiu J.N.Sun D.T.Su J.Wang c.wu Z.Xu X.M.Yang S.K.Zhang Z.Zhang N.Zhang Y.F.Zhu h.Y.Ban X.Z.Bi Z.M.cai W.chen X.chen Y.h.chen Y.cui X.L.Duan Z.G Feng Y.Gao J.W.he T.he J.J.huang F.Li J.S.Li T.J.Li T.T.Li h.Q.Liu L.Liu R.Liu S.Liu N.Meng Q.Shi A.T.Sun Y.M.Wang Y.B.Wang h.c.wu D.X Xu Y.Q Yang Y.Yang X.S.Yu K.X.Zhang Y.L.Zhang Y.h.Zhang Y.T.Zhang h.Zhou X.c.Zhu J.S.cheng L.Qin L.Wang Q.L.Wang M.Bai R.L.Gao Z.Ji Y.R.Liu F.L.Ma Y.J.Shi J.Su Y.Y.Tan J.Z.Tong h.T.Xu c.B.Xue G.F.Xue W.Yuan National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China North Night Vision Technology co. LTDNanjing 211106China Institute of high Energy Physics Chinese Academy of SciencesBeijing 100049China Science and Technology on Low-Light-Level Night Vision Laboratory Xi'an 710065China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201204China Institute of Electrical Engineering Chinese Academy of ScienceBeijing 100190China National Space Science center Chinese Academy of ScienceBeijing 100190China

The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(cMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWhM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 millicrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and cMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.

关键词： instrumentation detectors-space vehicles instruments-telescopes-X-rays genera

convexification of hybrid Ac-Dc Optimal Power Flow with Line-commutated converters

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cSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan Liang Zhigang Li J.h.Zheng Q.h.wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (Lcc)-based high-voltage Dc (hVDc) systems have been integrated with bulk Ac power grids for interregional transmission of renewable power. The nonlinear Lcc model brings additional nonconvexity to optimal power flow (OPF) of hybrid Ac-Dc power grids. A convexification method for the Lcc station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical Lcc station models that facilitates second-order cone convex relaxation for the OPF of Lcc-based Ac-Dc power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed Lcc station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： Ac-Dc power system convex relaxation linecommutated converter optimal power flow second-order cone programming

Astrocytic calcium waves:unveiling their roles in sleep and arousal modulation

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Neural Regeneration Research 2024年第5期19卷 984-987页

作者： Erxi wu Dan Qi Damir Nizamutdinov Jason h.huang Department of Neurosurgery and Neuroscience Institute Baylor Scott&White HealthTempleTXUSA Texas A&M University School of Medicine TempleTXUSA Texas A&M University School of Pharmacy College StationTXUSA LIVESTRONG cancer Institutes and Department of Oncology Dell Medical Schoolthe University of Texas at AustinAustinTXUSA Department of Neurosurgery Baylor College of MedicineTempleTXUSA

Neuron-astrocyte interactions are vital for the brain’s connectome.Understanding astrocyte activities is crucial for comprehending the complex neural network,particularly the population-level functions of neurons in different cortical states and associated behaviors in mammals.Studies on animal sleep and wakefulness have revealed distinct cortical synchrony patterns between neurons.Astrocytes,outnumbering neurons by nearly fivefold,support and regulate neuronal and synaptic function.Recent research on astrocyte activation during cortical state transitions has emphasized the influence of norepinephrine as a neurotransmitter and calcium waves as key components of ion channel signaling.This summary focuses on a few recent studies investigating astrocyte-neuron interactions in mouse models during sleep,wakefulness,and arousal levels,exploring the involvement of noradrenaline signaling,ion channels,and glutamatergic signaling in different cortical states.These findings highlight the significant impact of astrocytes on large-scale neuronal networks,influencing brain activity and responsiveness.Targeting astrocytic signaling pathways shows promise for treating sleep disorders and arousal dysregulation.More research is needed to understand astrocytic calcium signaling in different brain regions and its implications for dysregulated brain states,requiring future human studies to comprehensively investigate neuron-astrocyte interactions and pave the way for therapeutic interventions in sleep-and arousal-related disorders.

关键词： arousal astrocyte calcium waves locus coeruleus neuron-astrocyte interaction norepinephrine sleep wakefulness

A hybrid Signal Processing Method combining Mathematical Morphology and Walsh Theory for Power Quality Disturbance Detection and classification

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cSEE Journal of Power and Energy Systems 2024年第2期10卷 584-592页

作者： Zhi Ding Tianyao Ji Mengshi Li Q.h.wu School of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

In this paper, a novel signal processing method combining mathematical morphology (MM) and Walsh theory is proposed, which uses Walsh functions to control the structuring element (SE) and MM operators. Based on the Walsh-MM method, a scheme for power quality disturbances detection and classification is developed, which involves three steps: denoising, feature extraction and morphological clustering. First, various evolution rules of Walsh function are used to generate groups of SEs for the multiscale Walsh-ordered morphological operation, so the original signal can be denoised. Next, the fundamental wave of the denoised signal is suppressed by hadamard matrix;thus, disturbances can be extracted. Finally, the Walsh power spectrum of the waveform extracted in the previous step is calculated, and the parameters of which are taken by morphological clustering to classify the disturbances. Simulation results reveal the proposed scheme can effectively detect and classify disturbances, and the Walsh-MM method is less affected by noise and only involves simple calculation, which has a potential to be implemented in hardware and more suitable for real-time application.

关键词： hadamard matrix mathematical morphology morphological clustering power quality disturbance Walsh theory

hepatocardiorenal syndrome in liver cirrhosis:Recognition of a new entity?

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World Journal of Gastroenterology 2024年第2期30卷 128-136页

作者： henry h L wu Amina Rakisheva Arvind Ponnusamy Rajkumar chinnadurai Renal Research Kolling Institute of Medical ResearchRoyal North Shore Hospital&The University of SydneySt.Leonards(Sydney)2065New South WalesAustralia Department of cardiology City Cardiological CenterAlmaty 050000Kazakhstan Department of Renal Medicine Royal Preston HospitalPreston PR29HTUnited Kingdom Donal O’Donoghue Renal Research centre&Department of Renal Medicine Northern Care Alliance National Health Service Foundation TrustSalford M68HDUnited Kingdom

Emerging evidence and perspectives have pointed towards the heart playing an important role in hepatorenal syndrome(hRS),outside of conventional understanding that liver cirrhosis is traditionally considered the sole origin of a cascade of pathophysiological mechanisms directly affecting the kidneys in this context.In the absence of established heart disease,cirrhotic cardiomyopathy may occur more frequently in those with liver cirrhosis and kidney disease.It is a specific form of cardiac dysfunction characterized by blunted contractile responsiveness to stress stimuli and altered diastolic relaxation with electrophysiological abnormalities.Despite the clinical description of these potential cardiac-related complications of the liver,the role of the heart has traditionally been an overlooked aspect of circulatory dysfunction in hRS.Yet from a physiological sense,temporality(prior onset)of cardiorenal interactions in hRS and positive effects stemming from portosystemic shunting demonstrated an important role of the heart in the development and progression of kidney dysfunction in cirrhotic patients.In this review,we discuss current concepts surrounding how the heart may influence the development and progression of hRS,and the role of systemic inflammation and endothelial dysfunction causing circulatory dysfunction within this setting.The temporality of heart and kidney dysfunction in hRS will be discussed.For a subgroup of patients who receive portosystemic shunting,the dynamics of cardiorenal interactions following treatment is reviewed.continued research to determine the unknowns in this topic is anticipated,hopefully to further clarify the intricacies surrounding the liver-heart-kidney connection and improve strategies for management.

关键词： hepatorenal syndrome cardiorenal syndrome cirrhosis cardiac dysfunction circulatory dysfunction

Location of Asymmetric Ground Fault Using Virtual Injected current Ratio and Two-stage Recovery Strategy in Distribution Networks

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cSEE Journal of Power and Energy Systems 2024年第1期10卷 151-161页

作者： haiting Shan Luliang Zhang Q.h.wu Mengshi Li School of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

Sparse measurements challenge fault location in distribution networks.This paper proposes a method for asymmetric ground fault location in distribution networks with limited measurements.A virtual injected current vector is formulated to estimate the fault line,which can be reconstructed from voltage sags measured at a few buses using compressive sensing(cS).The relationship between the virtual injected current ratio(VIcR)and fault position is deduced from circuit analysis to pinpoint the fault.Furthermore,a two-stage recovery strategy is proposed for improving reconstruction accuracy of the current vector,where two different sensing matrixes are utilized to improve the incoherence.The proposed method is validated in IEEE 34 node test feeder.Simulation results show asymmetric ground fault type,resistance,fault position and access of distributed generators(DGs)do not significantly influence performance of our method.In addition,it works effectively under various scenarios of noisy measurement and line parameter error.Validations on 134 node test feeders prove the proposed method is also suitable for systems with more complex structure.

关键词： Distribution networks fault location reconstruction accuracy two-stage recovery virtual injected current ratio

Estimating critical clearing Time of Grid Faults Using DA of State-Reduction Model of Power Systems

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cSEE Journal of Power and Energy Systems 2024年第2期10卷 807-820页

作者： Yang Liu Zhongyang chen huanjin Yao Lin Yi Q.h.wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China china Southern Power Grid Research Institute Guangzhou 510663China

This paper proposes a critical clearing time (ccT) estimation method by the domain of attraction (DA) of a state-reduction model of power systems using sum of squares (SOS) programming. By exploiting the property of the Jacobian matrix and the structure of the boundary of the DA, it is found the DA of the state-reduction model and that of the full model of a power system are topological isomorphism. There are one-to-one correspondence relationships between the number of equilibrium points, the type of equilibrium points, and solutions of the two system models. Based on these findings, an expanding interior algorithm is proposed with SOS programming to estimate the DA of the state-reduction model. State trajectories of the full model can be transformed to those of the state-reduction model by orthogonal or equiradius projection. In this way, ccT of a grid fault is estimated with the DA of the state-reduction model. The calculational burden of SOS programming in the DA estimation using the state-reduction model is rather small compared with using the full model. Simulation results show the proposed expanding interior algorithm is able to provide a tight estimation of DA of power systems with higher accuracy and lower time costs.

关键词： critical clearing time domain of attraction expanding interior algorithm state-reduction model SOS programming